Setting the Standard: A Summary of Compost Standards in Canada

The establishment of product quality standards supports the long-term growth of an industry. The Canadian composting industry and government have developed compost quality criteria which will ensure product satisfaction and maintain consumer confidence. This is fundamental to the continued expansion and strengthening of the composting industry in Canada.

In Canada, three organizations are responsible for the development of standards and regulations for compost and composting: Agriculture and Agri-Food Canada (AAFC), the provincial and territorial governments, and the Standards Council of Canada (SCC) (through the Bureau de normalisation du Québec (BNQ)). This collective responsibility reflects government regulatory requirements (of both the AAFC and the provinces and territories) as well as voluntary industry initiatives (BNQ).

The scope of their responsibilities is as follows:
  • Agriculture and Agri-Food Canada (AAFC) regulates compost under the authority of the Fertilizers Act and Regulations. All compost that is sold in Canada must comply with the requirements of the Fertilizers Act. This includes provisions for product safety, benefit claims and labeling.
  • the provinces and territories regulate the disposal and use of waste, including its production and use. Consequently, compost which is produced and used is regulated within this jurisdication. The Canadian Council of Ministers of the Environment (CCME) assists to coordinate provincial and territorial initiatives wherever possible.
  • the BNQ, acting on behalf of the Standards Council of Canada, establishes voluntary industry standards and endorses products which meet these standards.

    The development of compost standards was coordinated by the three organizations to establish and maintain high standards for product quality and safety while maximizing uniformity thereby facilitating industry competitiveness. This innovative approach has resulted in the establishment of the following:

  • a National Standard of Canada entitled: Organic Soil Conditioners - Composts (BNQ);
  • Guidelines for Compost Quality (CCME); and
  • future amendments to the Fertilizers Act and Regulations (AAFC).

    These provide for a significant level of national consistency by containing virtually identical technical requirements while ensuring that the mandates and interests of the different organizations are realized.

    The standards are based on four criteria for product safety and quality: maturity, foreign matter, trace elements and pathogens.

    The purpose of this document is to provide a summary of the details of the 3 standards, identifying their similarities and areas of difference.

    Definition of Compost

    “Composting” and “compost” are two distinct terms. The former refers to the bio-oxidation process and the latter refers to the resulting product: stabilized organic matter.

    As agreed upon by the CCME, BNQ and AAFC, compost is:

     “A solid mature product resulting from composting, which is a managed process of bio-oxidation of a solid heterogeneous organic substrate including a thermophilic phase.”

    Classification of Compost

    The criteria for product safety is consistent across all the standards. The differences in compost types or categories reflect variances in product quality.

    Classification of Compost
      Category
    BNQ AA,A,B
    CCME (provinces & territories) A,B
    AAFC one category based on trace element limits of B

     

    BNQ Standard

    Under the BNQ Standard, compost may be classified in three ways: Types AA, A and B.

    The requirements for Type B compost are considered to be the minimum necessary to obtain a good compost. Compost classified as Types AA and A is of higher quality.

    Foreign matter content is the distinguishing factor between the three types. Trace element content is the classification feature which differs Types AA, A compost from Type B compost.

    CCME Guideline


    Within the CCME Guideline, two compost categories have been established: Category A and B. This reflects differences in trace element concentrations.

    Category A compost can be used for all types of applications: on agricultural lands, in residential gardens, in horticultural operations, in nurseries or other enterprises. Category A criteria for trace elements are achievable using source separated municipal solid waste feedstock.

    Category B compost has restricted use. Its use may be controlled under provincial or territorial regulations.

    AAFC Regulation

    The AAFC recognizes only one class of compost, reflective of product safety criteria. It is based on the limits of Category and Type B compost for trace elements and reflects the requirements of the standards on pathogenic organisms, maturity and the presence of sharp objects.

    The Four Criteria: Maturity, Foreign Matter, Trace Elements and Pathogens

    I. Maturity


    Compost maturity is fundamental to the classification of the product. Several indicators are necessary to determine compost maturity. The BNQ/CCME/AAFC standards use the same compost maturity indicator tests. The CCME guidelines also have identified additional criteria which may be used instead, and which reflect criteria already in existence in certain provinces.

    The compost maturity indicator tests which are recognized by all three organizations (BNQ, CCME, AAFC) are as follows:

     Compost is deemed mature if it meets 2 of the following requirements:
  • C/N ratio <= 25;
  • oxygen uptake rate <= 150 mg O2/kg volatile solids per hour; and
  • germination of cress (Lepidium sativum) seeds and of radish (Raphanus sativus) seeds in compost must be greater than 90 percent of the germination rate of the control sample, and the growth rate of plants grown in a mixture of compost and soil must not differ more than 50 percent in comparison with the control sample.

    The CCME guideline also identifies the following criteria which may be used instead of the above to confirm compost maturity:
  • Compost must be cured for at least 21 days; and
  • Compost will not reheat upon standing to greater than 20°C above ambient temperature.
    OR


  • Compost must be cured for at least 21 days; and
  • Reduction of organic matter must be > 60 percent by weight.
    OR

  • If no other determination of maturity is made, the compost must be cured for a six month period. The state of the curing pile must be conducive to aerobic biological activity. The curing stage begins when the pathogenic reduction process is complete and the compost no longer reheats to thermophilic temperatures.

    II. Foreign Matter



    Foreign matter is defined as:

    “Any matter over a 2 mm dimension that results from human intervention and having organic or inorganic constituents such as metal, glass and synthetic polymers (e.g. plastic and rubber) that may be present in the compost but excluding mineral soils, woody material and rocks.”

    Safety and aesthetics constitute the key considerations in the development of foreign matter content standards in compost.

    The safety criteria, relating to sharp foreign matter content, are similar across the BNQ, CCME and AAFC standards.

    The BNQ standards establish three different foreign matter mass content limits for Types AA, A and B compost, reflective of product aesthetics. The CCME guidelines also identify a limit for foreign matter content which is the same as the maximum dimension allowed by BNQ (25 mm) (table b).

    FOREIGN MATTER -- SAFETY CRITERIA

    Compost must not contain any sharp foreign matter measuring over a 3 mm dimension that may cause damage or injury to humans, animals and plants during or resulting from its intended use.

    Compost must not contain any sharp foreign matter measuring over a 3 mm dimension that may cause damage or injury to humans, animals and plants during or resulting from its intended use.

    FOREIGN MATTER -- AESTHETICS

    BNQ Standard
    Type AA Type A Type B
    Foreign matter content as
    a percentage of oven-dried mass
    <= 0.01
    <= 0.5
    <= 1.5
    Foreign matter, maximum
    dimensions, in mm
    12.5
    12.5
    25


    CCME Guideline

    The compost must not contain any foreign matter greater than 25 mm in any dimension.

    III. Trace Elements


    A “trace element” is defined as “a chemical element present in compost at a very low concentration.” The compost standards identify trace elements that are essential to plant growth in addition to identifying heavy metals which, depending on their concentration in the soil, could be harmful to human health and the environment.

    The similarities across the BNQ, CCME and AAFC criteria for trace elements are significant.

    The BNQ Types AA and A are identical to the CCME Category A. The B classificaiton is similar across all 3 standards with the exception that maximum permissible concentrations for chromium and copper are not identified by AAFC and CCME, having yet to be established by AAFC under the Fertilizers Act.

    The maximum cumulative additions to the soil are the same across the standards although its not specifically referenced in the BNQ standards. This reflects the fact that the BNQ standards deal with product-specifics only.

    It is recognized that additional elements may be added to the list according to the availability of new scientific data.
    Table 2: Maximum Trace Element Concentration Limits for Compost
    BNQ                            CCME
    Types AA and A

    Category A
    		BNQ              CCME         AAFC
    Type B**

    Category B² Maximum Acceptable

    Concentrations within Product
    Trace
    Elements*
    (mg/kg, air-dried mass)
    (mg/kg, air-dried mass)
    Arsenic (As)
    13
    75
    Cadmium (Cd)
    3
    20
    Cobalt (Co)
    34
    150
    Chromium (Cr)
    210
    1,060
    (BNQ only); not stated in CCME/AAFC
    Copper (Cu)
    100
    757
    (BNQ only); not stated in CCME/AAFC
    Mercury (Hg)
    0.8
    5
    Molybdenum (Mo)
    5
    20
    Nickel (Ni)
    62
    180
    Lead (Pb)
    150
    500
    Selenium (Se)
    2
    14
    Zinc (Zn)
    500
    1,850

    *Other elements, such as boron, manganese, aluminum and iron, may eventually be regulated in certain provinces to accomodate regional and national concerns.
    **Type B limits for maximum trace element concentrations in compost are based on the standards enforced by AAFC under Trade Memorandum T-4-93 since 1979.

    Table 3: Maximum Cumulative Metal Additions to Soil
     CCME                        AAFC
    Trace Elements*  (kg/ha)
    Arsenic (As)
    15
    Cadmium (Cd)
    4
    Chromium (Cr)
    **
    Copper (Cu)
    **
    Mercury (Hg)
    1
    Molybdenum (Mo)
    4
    Nickel (Ni)
    36
    Lead (Pb)
    100
    Selenium (Se)
    2.8
    Zinc (Zn)
    370

    *Other elements, such as boron, maganese, aluminum and iron, may be eventually be regulated in certain provinces to accomodate regional and national concerns.

    **Limits for copper and chromium are not established in the Fertilizers Act. Agriculture and Agri-Food Canada will be conducting a consultation process for adopting limits for chromium and copper. The CCME will re-evaluate these parameters when this process is complete.

    IV. Pathogens

    Pathogenic organisms are sometimes present in the feedstocks used to make compost. As a result, the compost may also contain pathogens. To reduce any potential health concerns, treatment processes as well as biological specifications have been identified.

    All 3 standards (BNQ, CCME, AAFC) identify that the pathogenic organism content must not exceed the following limits:
  • the quantity of faecal coliforms must be < 1,000 Most Probable Number (MPN)/g of total solids calculated on a dry weight basis; and
  • there can be no salmonellae present ( < 3 MPN/4g total solids).

    Reflective of its ability to regulate and monitor processs, the CCME has also identified additional process guidelines to be followed to meet pathogen limits. The process choice reflects both the feedstock in addition to the composting method being used.

    Within the CCME guideline, if the compost does not originate from feedstock known to be high in human pathogens, either a test may be conducted to meet the limits identified above (similar to BNQ and AAFC) or the following process may be done:
  • Using the in-vessel composting method, the solid waste shall be maintained at operating conditions of 55°C or greater for three days.
  • Using the windrow composting method, the solid waste shall attain a temperature of 55°C or greater for at least 15 days during the composting period. Also, during the high temperature period, the windrow shall be turned at least five times.
  • Using the aerated static pile composting method, the solid waste will be maintained at operating conditions of 55°C or greater for three days. The preferable practice is to cover the pile with an insulating layer of material, such as cured compost or wood chips, to ensure that all areas of the feed material are exposed to the required temperature.

    If the compost contains feedstock known to be high in human pathogens, it must not exceed the identified limits for faecal coliforms or be abset of salmonellae as well as undergo the composting process identified above or other treatment as identifid by the relevant province or territory.
    The above summary has been designed to provide an overview of the three standards. Prior to embarking on a specific course of action, members of the composting industry should refer to the documentation produced by each of the three organizations (BNQ, CCME, AAFC).


    BNQ:      CAN/BNQ 0413-200-M95
                    Amendement organiques - Compost (Organic Soil Conditioners - Compost)

                    Contact: Bureau de normalisation du Québec
                    333, rue Franquet
                    Sainte-Foy, Québec G1P 4C7
                    Ph: (418) 652 2238
                    Fax: (418) 652 2292

    CCME:   Guidelines for Compost Quality
                    CCME-106E

                    Contact: CCME Documents
                    c/o Manitoba Statutory Publications
                    200 Vaughn Street
                    Winnipeg, Manitoba R3C 1T5
                    Ph: (204) 945 4664
                    Fax: (204) 945 7172


    AAFC:   A consultation process is underway at AAFC to amend the Fertilizers Regulations to reflect the identified compost standards. For further information, please contact:

                    Fertilizer Section, Plant Products Division
                    Agriculture and Agri-Food Canada
                    59 Camelot Drive, 3rd Floor, East
                    Ottawa, Ontario K1A 0Y9
                    Ph: (613) 952 8000
                    Fax: (613) 992 5219